Boot measured pipe Q402 (D1887) b, c and e are breakdown, detection C405, C406, C407, D401, D402 are no exception, with authentic D1887 manager measured after the power supply is normal (e.g. + 130 V, + 30 V and + 13.5 V, etc.), the indicator light flashing after shutdown, no other response. 5YQservice manual download site
Take a closer look at the machine line circuit, draw the machine line driver circuit is shown in figure 1, 5YQservice manual download site
 5YQservice manual download site
Found the machine line driver circuit consists of TDA8143, circuit is simplified, measuring TDA81431 approximate short circuit, 2, 3 feet. According to drawings, pipe breakdown after + 130 v voltage by Q402 b, R401 Ω (27) into TDA81432 feet (foot) output, the ICE working voltage is only 13 v, 130 v + + add 2 feet and make TDA8143 damage. 5YQservice manual download site
 5YQservice manual download site
TDA8143 is difficult to buy, he decided to try to use other circuit substitution the ICE. Chad D1887 for undamped pipe, remove the TDA8143, check data, draw new circuit is shown in figure 2. After debugging repeatedly to determine the value of each component parameters as shown in figure 2 respectively, T1 is a regular line of excitation transformer and other components have no other special requirements, with a small piece of printing plate welding related components. With A ribbon cable that connected the new board and main board, the disconnection of figure 1 A, will pick D1887 figure 2 B point B, the new power supply from the board motherboard + 30 v, the input (H, DTRE) from the motherboard TDA81438 feet, termination TDA8143D1 feet, will be the new plate fixed in the machine, after repeated trial proved that the circuit could substitution TDA8143. As for the IC in the future, will be A spot welding, tear down the new board.5YQservice manual download site